蛇形填数之倒填

#include<stdio.h>#include<string.h>#define MAXN 30int a[MAXN][MAXN];int main(){int n,x,y,tot=0;while(~scanf("%d",&n)){memset(a,0,sizeof(a));tot=a[x=n-1][y=n-1]=1;while(tot<n*n){while(x>=0){while(y-1>=0)   a[x][--y]=++tot;x-=1;y=n;}}for(x=0;x<n;x++){for(y=0;y<n;y++)printf("%3d",a[x][y]);printf("\n");}}}